Electric welding apparatus



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Patented Mar. 27,1928,

ALEXANDER cnuacnwhnn, or-nnwjyoax, it. 2.,

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' Application filed February 17, 1921. semi Io. 10am.

This invention relates to' electric welding apparatus, and has particular reference to an auxiliary regulating means for such apparatus.

According to current furnished by the direct current generator of an electric welding ap aratus is entirely controlled by means, usua ly a field rheostat, located'on the control panel of the machine. Before commencing a weldin operation, the operator adjusts such contro means so that the generator will furnish the current which the operator regards as desirable for the particular kind of work in hand. It often happens, however, that the welding current changes during the welding operation due, for example, to changes in the voltage of the current supplied by a power circuit to the motor which drives the welding generator, and the operator finds it necessary to adjust thefield rheostat or the control panelin order to keep the welding. current at the desired value. Even when the welding workis locatednear the control panel of the welding machine, such adjustments take the operator from his work and result in loss of his time; but when the work is located at a distance from the control panel, as is often the case, it is particularly 3Q inconvenient for the operator to go to the control panel and readjust the welding current, and he loses considerable time from his welding work if he does so.

The general object of the present invention is to provide a simple and eflicient aux iliary regulating means, which is always within easy reach of the.welding operator regardless of where the work may be located; and the invention is characterized by the fact that such auxiliary regulating means is incorporated'in and constitutes a part of anelectrode holder which is held by the operator during the welding work and is therefore always conveniently located 15 with reference tohim.

Other objects and advantages of the invention will become apparent from the following description, taken in connection with the accompanying drawings in which, Figure 1 is a longitudinal, central, sectional view or" a combined control means and electrode holder. Figure 2 is a transverse, sectional view taken on the line 2-2 of Fig- 1. Figure 3 is a diagrammatic view oi usual practice, the welding handle portion 18 of the or ports 24 formed in the housing a welding circuit with which the combined control means and electrode holder is adapted to be used.

Referring to Figure 3, the-combined control means and electrode holder 4 is illustrated in connection with a welding apparatus in which 5 indicates the armature, 6 the intergiole series field, and 7 the main series fiel of an undercom ounded direct current enerator having a s unt field 8 capable 0 being regulated by an adjustable rheostat 9 located on the control panel of the machine. One of the generator brushes is shown connected with a. part 11 to be welded, and the other generator brush is shownconnected to av welding electrode 12 through the series field windings 6 and 7, a reactance 13 located in the welding circuit, and certain elements of the combined controlmeans and electrode holder hereinafter more particular] described.

- Referring to igure 1, the combined control means and electrode holder 4 includes a pairvof" fingers 15, between which the electrode. 12 is gripped the fingers 15 being connected to a rotatable head 16, to which is suitably connected a disc 17 preferably of insulating material, by means of which the head 16 may be rotated with respect to the holder, which is made'of a suitable insulatin material and serves as a housing for an a justable rheostat 19 -made up of a pluralit of carbon discs 19' The head 16 molu es an internally screw-threaded flan e 20, which is adapted for screw-thread connection with the xteriorly screw-threaded end of a barrel 2 secured to the housing 18 by screws 21'- or the like, passing through an annular spacing ring 22, which serves to maintain the barrel 21 in a spaced relation to the housin 18, thus providing. an air space 23 which is vented by a plurality of openings 18. Into one end of the barrel 21 is fitted a metallic abutment or terminal 25, which may be secured to the metallic barrel 21 by the same screws 21 that are employed to secure the barrel 21 to the housing 18. This abutment or terminal 25 is adapted for connection with the hared end of a welding cable 26, which constitutes that portion of the welding circuit shown in Figure. 3, as leadmg from the reactance to the cam bined control means and electrode holder 4 and is provided with an opening 28, adapted for the reception of an lnsulated conductor 29 leading from the rheostat 9 to a metallic compression disc 30, having a stem 31 which is received by an insulating washer 32, adapted to prevent direct electrical connection of the open end of the abutment 25 with thecompression disc 30. The carbon discs 19' are insulated from the barrel 21 by reason of the fact that they are carried within an insulating tube 33, which is adapted to snugly fit the metallic tube 21 and engage one end of the abutment 25. The opposite end of the insulating tube 33 carries a metallic compression disc" 35, having a stem 36, which projects'through a suitable washer or guided? of insulatin material carried within the insulating tube 33, the projecting end of the stem 36 being adapted to engage a tapered projection 38 carried by the rotatable head 16.

The welding circuit may be traced, from one brush of the generator, through the series fields (5 and 7 and the reactance lilto the point of connection of the cable 26 with the abutment 25, and then through the abutment 25, metallic barrel 21, and the head 16 to the welding electrode 12, the welding circuit be ing ,completed through the work 11 to the other brush of the generator. The shunt field circuit may be traced from one brush of the generator, through the shunt field 8, panel board rheostat 9, wire 29, stem 31, disc 30, the several carbon discs 19', disc 35, stem 36, projection 38, head 16, barrel 21, abutment 25 to the cable 26 connected to the other brush of the generator through the reactance 13 and the series fields 'Z and 6.

, From the above description it will be appreciated that by varying the pressure upon the carbon discs 19', by rotating the housing 18 one way or the other with respect to the head 16, the resistance in the shunt field winding 8 may be easily varied by the operator, without leaving his work, to elfect the desired control of the welding current, as circumstances may require.

What is claimed is:

1. For use in electric welding, a combined electrode holder and shunt field resistance comprising a handle portion, a resistance element housed therein, means manually operable from the exterior of said handle portion for varying the resistance of said resistance element, and means for holding comprising a handle portion, means movably supported on said handle portion for holding an electrode, and a resistance element housed within said handle portion and varied in resistance by relative movement of said handle portion and said electrode holding means.

3. For use in electric welding, a combined electrgdc holder and shunt field resistance comprising a. handle portion, an electrode holding means rotatably mounted on said handle portion, a resistance element housed within said handle portion, and means rooperating with said resistance element and said electrode holding means for varying the resistance of said resistance element by the relative rotation of said handle portion and said electrode holding means.

l. For use in electric welding, a combined electrode holder and shunt field resistance comprising a handle portion, having a housing, a carbon pile resistance element arranged within said housing, an electrode holder with which said handle portion is rotatably connected, and means within said housing cooperating with said carbon pile resistance and said electrode holder for varying the resistance of the carbon pile by relative rotation of said handle portion and said electrode holding means.

5. For use in electric welding, 51. combined electrode holder and shunt field resistance con'iprising a handle portion, a metal barrel therein adapted to be'electrically connected to an electric cable, an electrode holder rotatably connected to said barrel, a carbon pile resistance element arranged within said barrel and insulated therefrom and adapted to be connected at one end to an electric conductor, and means for connecting the other end of said carbon pile to said electrode holder and for varying the pressure of said carbon pile as the handle portion and electrode holder are rotated with reference to one another. I

In testimony whereof, I have affixed my signature to this specification.

ALEXANDER CHURCHWARD. 

